[Octave-bug-tracker] [bug #49667] Computing powers of complex numbers in 4.2.0 is slower than in 4.0.3

[Avinoam Kalma]

Follow-up Comment #2, bug #49667 (project octave):

Checking on Win-10 32 bit:

4.0.3:


>>  z=rand(1000)+1i*rand(1000);
>> tic,z.*z;,toc,tic,z.^2;,toc,tic,exp(2*log(z));,toc
Elapsed time is 0.029856 seconds.
Elapsed time is 0.0566921 seconds.
Elapsed time is 0.470668 seconds.
>> tic,z.*z;,toc,tic,z.^2;,toc,tic,exp(2*log(z));,toc
Elapsed time is 0.019012 seconds.
Elapsed time is 0.046031 seconds.
Elapsed time is 0.454301 seconds.
>> tic,z.*z;,toc,tic,z.^2;,toc,tic,exp(2*log(z));,toc
Elapsed time is 0.0210109 seconds.
Elapsed time is 0.04603 seconds.
Elapsed time is 0.449299 seconds.
>> tic,z.*z;,toc,tic,z.^2;,toc,tic,exp(2*log(z));,toc
Elapsed time is 0.02001 seconds.
Elapsed time is 0.046031 seconds.
Elapsed time is 0.450298 seconds.
>> tic,z.*z;,toc,tic,z.^2;,toc,tic,exp(2*log(z));,toc
Elapsed time is 0.02001 seconds.
Elapsed time is 0.0450299 seconds.
Elapsed time is 0.450299 seconds.


4.2.0:


>>  z=rand(1000)+1i*rand(1000);
>> tic,z.*z;,toc,tic,z.^2;,toc,tic,exp(2*log(z));,toc
Elapsed time is 0.018013 seconds.
Elapsed time is 0.040025 seconds.
Elapsed time is 0.42469 seconds.
>> tic,z.*z;,toc,tic,z.^2;,toc,tic,exp(2*log(z));,toc
Elapsed time is 0.0192781 seconds.
Elapsed time is 0.040027 seconds.
Elapsed time is 0.423281 seconds.
>> tic,z.*z;,toc,tic,z.^2;,toc,tic,exp(2*log(z));,toc
Elapsed time is 0.019012 seconds.
Elapsed time is 0.040027 seconds.
Elapsed time is 0.423281 seconds.
>> tic,z.*z;,toc,tic,z.^2;,toc,tic,exp(2*log(z));,toc
Elapsed time is 0.0184521 seconds.
Elapsed time is 0.0410269 seconds.
Elapsed time is 0.42228 seconds.


There is no noticeable difference. 

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